Hello all.

Looking to purchase two remote temp sensors for my ATP32UO4 CM t-stat.

My plan is to install one for outside temp to control my humidity.

The other is for a indoor remote temp sensor. We have a gas fireplace and when in use it messes with the t-stat causing the rest of the house to cool off.  Would a remote temp sensor be able to call for heat or is it only a display?  The plan is to put it in a room away from the fireplace.  We currently run the blower when the FP is on but it does not pull enough heat away from the room with the t-stat. 

Thanks in advance. Kurt

Best bet would be to relocate the Tstat.
Honeywell makes a wireless model.
j

Move the stat.

Was thinking thats what I would get for answer. LOL. Already moved it from its original location right above cold air return. The only other place would be in the master bedroom which is always cooler. I really like the options and controls of this stat, dont really want to replace.

Does anyine know if the remote indoor temp can call for heat??

Kurt

Here's a thought - leave it where it is but put a remote sensor in the cold air return - the mixing air might overcome the effect of the gas FP

That would probably be the easiest route. But, would that cause issues with the second stage coming on due to the temp of the return air when really stage 1 could handle it? I guess i could change the temp differential for stage 2 activation. Right now my t-stat is set to 70, return air is 68. If that was the reading I would be in stage 2.

Does the t-stat average the 2 readings if a remote sensor is installed?

You could turn the thermostat up higher when you run the fireplace.
The temp disparity will be there regardless of tstat or remote sensor location.
j

I don't know the answer to the averaging question - I'd hope it is configurable

Since return air runs a bit cooler than what the thermostat sees, the simple answer is to lower the thermostat set point. The object is to be comfortable, not achieve an arbitrary number sensed by a thermostat.

If you are moderately handy, experiment with adding a pigtail to the stat wire and temporarily putting the stat in the return air duct. Be certain not to cross up any connections or you could let the smoke out of the stat or control power transformer.

Looking back at your original post, you ask about using a second sensor mounted outdoors in order to control humidity. How would that work?

Yeh, looking at the sensor its just a 10k based sensor, i may pick one up at radioshack and experiment.
As far as humidity, the t-stat will adjust humidification settings based on the outside air temp. Just another feature that would be nice to have working.
Kurt

The spec is for a 'normal' J Curve, NTC 10K @ 25 C (2 wire)

I got mine off of ebay:
2 pcs Thermistor in #6 Lug, 10K @ 25 C, J Curve, NTC

I only hook up the outside one... The other one is laying here on the computer table.  Doc doesn't say how the remote indoor sensor is used.

Posted By kmsss on 05 Feb 2011 10:41 PM
Does anyine know if the remote indoor temp can call for heat??

You'll have to read the manual for that particular t-stat.

On some (most?) Honeywell t-stats, the remote indoor sensor
(if attached) takes over entirely, and the built-in local sensor
is ignored.

Posted By kmsss on 05 Feb 2011 11:17 PM
Does the t-stat average the 2 readings if a remote sensor is installed?

I just read the manual for this thermostat.  It doesn't mention averaging.  You may need to call CM technical support for a definitive answer.  I agree with Looby - Honeywells will also average the readings if multiple indoor remote sensors are used.

If you want flexibility to use either the thermostat or the remote sensor for temperature readings, perhaps you could put an appropriately rated on/off switch in the wiring of the remote sensor (assuming you cannot otherwise select the temperature read location through the thermostat menus.)  "On" may read from the remote sensor, and "off" may read from the thermostat.  Disclaimer:  A qualified electrician needs to confirm this would work and be safe.

Although expensive, some thermostats, like the Honeywell Prestige, have an option for a wireless outdoor sensor, and a wireless indoor remote thermostat that has a temperature sensor built in.  We have two of these systems (one for each of our geothermal units.)  Here is a link:

http://www.prothermostats.com/product.php?p=honeywell_ythx9321r5003&product=172899&category=1867

If you can find a good location for your indoor remote sensor, it should work fine (and be much cheaper).

Thanks Everyone. I will let u know the outcome when I get around to installing remote temps.
Keep up the good work!!

kmsss - assume you have the fan on manual to keep circulating the air when the fp is on, is there any way to add a return air over or near the f.p.? We have done this with standard forced air furnaces when customers complain about cold basements when using the fireplace or wood stove.

Posted By FBBP on 09 Feb 2011 09:57 PM
kmsss - assume you have the fan on manual to keep circulating the air when the fp is on, is there any way to add a return air over or near the f.p.? We have done this with standard forced air furnaces when customers complain about cold basements when using the fireplace or wood stove.

That is possible.  The only problem would be getting a large enough branch off the main over there. Otherwise, without a booster fan I dont think it would make a difference being so far from the return air main trunk.

Another idea would be to get right into the FP box with some ducting.  Instead of running the blower fan to vent around the fireplace it would just pump it into the return air..  Not sure if there would be any code/safety issues with that though!

Check with local inspector before putting a return too close to a fireplace. Many areas prohibit it to avoid venting problems or circulation of combustion products through out the home (if something goes wrong).
j

Back to the remote sensor issue. For commercial zone panels/thermostats that take a 10k remote sensor input, you can wire mutliple sensors in way that they are self averaging and appears as one sensor to the panel or thermostat. To do this you need at least (4), if you want more the next increment is (9). Don't let the quanitity scare you off the bullet type that you set above a ceilling or stick in ductwork are very cheap! And if you really have only (2) different places where you want readings averaged, you can set 2 right next to each other at both places.

I'm planning to do this if I get a fire place in my basement someday.

Just a thought....